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Reactions of adult humans to cries of normal and abnormal infants
INFANT BEHAVIOR AND DEVELOPMENT I, 2 2 4 - 2 2 7 (1978)
Reactions of Adult Humans to Cries of Normal and Abnormal Infants* RODNEY P. FREUDENBERG JANIS WILEY DRISCOLL AND GARY S. STERN
University o f Colorado at Denver Questionnaire responses of adult humans to the cries of normal and abnormal infants were examined. Forty-two college students, male and female, experienced and inexperienced with infants were exposed to the recorded cries of normal and Down's syndrome infants. Subjects rated the cries as to how unpleasant they were and how much the infant producing the cry needed attention. While all cries were rated as unpleasant, cries produced by normal infants were rated more unpleasant than cries produced by Down's syndrome infants. Normal infants were also rated to be in greater need of attention than Down's syndrome infants. Neither sex of subject nor the subjects' experience with infants affected the ratings. The infant cry as an elicitor of care-givingbehavior and as a negative reinforcer is discussed.
Previous research has demonstrated that the cries of abnormal infants differ from those of normal infants along a variety of dimensions (Haber, Davies, & Karelitz, 1966; Karelitz & Fisichelli, 1962; Wasz-H6ckert, Lind, Vuorenkoski, Partanen, & Valanne, 1968), In addition, several researchers have examined the reactions of adult humans to normal infant cries (Formby, 1967; MOiler, Hollien, & Murry, 1974; Wasz-H6ckert et al., 1968). However, responses of adults to the cries of normal and abnormal infants have not been compared. Common sense would suggest that the cries of abnormal infants would elicit more attentiongiving behaviors than the cries of normal infants since abnormal infants may need more attention. Yet, if human infants evolved the most effective careeliciting cry, any deviation from the normal cry may be a weaker elicitor of caregiving behavior in adults. On this basis, one would expect the cry of an abnormal infant to be a less effective stimulus in evoking parental behavior than the cry of a normal infant. It is also of interest to explore whether h u m a n infant cries are perceived as aversive and if there is a difference in the perceived aversiveness of *Paper presented at the 1976 meeting of the Animal Behavior Society, Boulder, Colorado. Requests for reprints should be addressed to J. W. Driscoll, University of Colorado at Denver, Denver, Co. 80202.
224
REACTIONS OF ADULTS TO INFANT CRIES
225
the cries of normal and abnormal infants. The questionnaire responses of adult humans to tape recorded cries of normal and Down's syndrome infants were employed to answer these questions.
METHOD The subjects were 21 male and 21 female college students, ranging in age from 20 to 36 years. Half of the subjects reported little previous experience with infants; the other half reported moderate to extensive experience. The recorded cries of 6 normal and 6 Down's syndrome infants were obtained from tapes prepared by Karelitz. l The cries of normal and Down's syndrome infants were matched for age of infant, intensity, and duration (10 sec). The 12 infant cries were presented in a random order to all subjects as a group in one session. After each cry, the subjects responded to two questionnaire items: (1) "How strong is your feeling that this infant needs immediate attention?" and (2) "How pleasant or unpleasant does this infant's vocalization sound to you?" The order of the questionnaire items was counterbalanced. Subjects rated these items on 9-point rating scales anchored at the extremes and the midpoint. The scales were described as possessing equal-appearing intervals. After the subjects had completed the rating scales, the nature of the study was explained. In summary, the experimental design included the following independent variables: Cry stimulus (normal versus Down's syndrome), sex of subject, and amount of experience with infants yielding a 2 x 2 x 2 factorial analysis of variance design with repeated measures on the first factor. Separate analyses were conducted on each questionnaire item. Since neither questionnaire item was affected by sex of subject or amount of experience with infants, data were pooled across these variables.
RESULTS AND DISCUSSION The original question addressed by this research was whether adult humans could discriminate the cries of normal and Down's syndrome infants. The answer is clearly that they can. Analysis of responses to the question regarding the infant's need for attention revealed a significant main effect of cry stimulus (F(1,41) = 31.94, p < .001). Normal cries elicited a higher rating that the infant 1Tapes obtained from National Medical Audio-Visual Center, Media Services Section, 1600 Clifton Rd. N.E., Atlanta, Georgia 30333. The cries were elicited by "gentle flicks" to the sole of the infant's foot. No information regarding the sex of infants providing the cries was given on the tapes.
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needed immediate attention (X = 5.90, SD = 1.57) than did Down's syndrome cries (X = 4.60, SD = 1.30). Analysis of ratings of the unpleasantness of the cries also revealed amain e.ffect of cry stimulus (F(1,41) = 26.92, p < .001). Although all cries were rated as unpleasant, the normal infant cries were rated more unpleasant (X = 7,06, SD = 1.04) than were Down's syndrome cries (X = 6.33, SD = 1.25). Responses to the attention and unpleasantness measures were correlated (r(40) = .38, p < .05), indicating that the more unpleasant a cry was rated, the more the infant was perceived as needing attention. In the present study, responses to artificial stimuli were measured. If such responses reflect natural behavior, the findings suggest that adult humans perceive the cries of normal infants as stronger signals for: care-giving behavior than those of Down's syndrome infants. Because amount of experience with infants did not affect reactions to the cries, there may be an unlearned component to this differential response. The ability to discriminate the cries of normal and abnormal infants may have adaptive significance for human evolution in that the energy expended in raising an abnormal infant is biologically wasted. On the other hand, these results may be specific to the fiat, lower pitched cries of Down's syndrome infants and may not reflect a general ability to discriminate between the cries of normal and abnormal infants other than Down's syndrome. It was found that although both sets of cries were perceived as unpleasant, the normal infant cries were rated more unpleasant than the Down's syndrome cries. This finding suggests that the termination of the cry may be negatively reinforcing such that care-giving behaviors that produce cessation of the cry may be increased in frequency. An undifferentiated care-giving response may be shaped by this negative reinforcer. The nonspecific nature of the care-giving response is suggested by previous research (M/iller, Hollien, & Murry, 1974) indicating that adult human females were unable to discriminate among cries elicited by different stimuli even when the cries were produced by their own infants. Although some investigators (Wasz-H6ckert et al., 1968) claim that "hunger" and "pain" cries of infants can be spectrographically differentiated, it is not clear that adult humans discrirninate cry types. It may be that in natural settings, situational stimuli provide more information about the elicitor of the infant's cry. That amount of experience with infants and sex of subjects or their interaction were not related to either questionnaire item may be due to the range of stimuli used. The cry stimuli may have been so distinct from one another as to render the discrimination easy for most subjects regardless of sex and amount of experience with infants. A study employing finer gradations of cry stimuli may provide a more sensitive test of the effects of these variables.
REACTIONS OF ADULTS TO INFANT CRIES
227
REFERENCES Formby, D. Maternal recognition of infant's cry. Developmental Medicine and Child Neurology, 1967, 9, 293-298. Haber, A., Davies, J., & Karelitz, S. Audible characteristics of the cries of normal infants and those with Down's syndrome. Perceptual and Motor Skills, 1966, 23, 745. Karelitz, S., & Fisichelli, V. R. The cry thresholds of normal infants and those with brain damage. Journal o f Pediatrics, 1962, 35, 802. M//ller, E., Hollien, H., & Murry, T. Perceptual responses to infant crying: Identification of cry types. Journal o f Child Lamguage, 1974, 1, 89-95. Wasz-H~ckert, O., Lind, J., Vuorenkoski, V., Partanen, T., & Valanne, E. The infant cry: A spectrographic and auditory analysis. Lavenham: Spastics International Medical Publ. in association with William Heinemann Medical Books Ltd., 1968.
Reactions of Adult Humans to Cries of Normal and Abnormal Infants* RODNEY P. FREUDENBERG JANIS WILEY DRISCOLL AND GARY S. STERN
University o f Colorado at Denver Questionnaire responses of adult humans to the cries of normal and abnormal infants were examined. Forty-two college students, male and female, experienced and inexperienced with infants were exposed to the recorded cries of normal and Down's syndrome infants. Subjects rated the cries as to how unpleasant they were and how much the infant producing the cry needed attention. While all cries were rated as unpleasant, cries produced by normal infants were rated more unpleasant than cries produced by Down's syndrome infants. Normal infants were also rated to be in greater need of attention than Down's syndrome infants. Neither sex of subject nor the subjects' experience with infants affected the ratings. The infant cry as an elicitor of care-givingbehavior and as a negative reinforcer is discussed.
Previous research has demonstrated that the cries of abnormal infants differ from those of normal infants along a variety of dimensions (Haber, Davies, & Karelitz, 1966; Karelitz & Fisichelli, 1962; Wasz-H6ckert, Lind, Vuorenkoski, Partanen, & Valanne, 1968), In addition, several researchers have examined the reactions of adult humans to normal infant cries (Formby, 1967; MOiler, Hollien, & Murry, 1974; Wasz-H6ckert et al., 1968). However, responses of adults to the cries of normal and abnormal infants have not been compared. Common sense would suggest that the cries of abnormal infants would elicit more attentiongiving behaviors than the cries of normal infants since abnormal infants may need more attention. Yet, if human infants evolved the most effective careeliciting cry, any deviation from the normal cry may be a weaker elicitor of caregiving behavior in adults. On this basis, one would expect the cry of an abnormal infant to be a less effective stimulus in evoking parental behavior than the cry of a normal infant. It is also of interest to explore whether h u m a n infant cries are perceived as aversive and if there is a difference in the perceived aversiveness of *Paper presented at the 1976 meeting of the Animal Behavior Society, Boulder, Colorado. Requests for reprints should be addressed to J. W. Driscoll, University of Colorado at Denver, Denver, Co. 80202.
224
REACTIONS OF ADULTS TO INFANT CRIES
225
the cries of normal and abnormal infants. The questionnaire responses of adult humans to tape recorded cries of normal and Down's syndrome infants were employed to answer these questions.
METHOD The subjects were 21 male and 21 female college students, ranging in age from 20 to 36 years. Half of the subjects reported little previous experience with infants; the other half reported moderate to extensive experience. The recorded cries of 6 normal and 6 Down's syndrome infants were obtained from tapes prepared by Karelitz. l The cries of normal and Down's syndrome infants were matched for age of infant, intensity, and duration (10 sec). The 12 infant cries were presented in a random order to all subjects as a group in one session. After each cry, the subjects responded to two questionnaire items: (1) "How strong is your feeling that this infant needs immediate attention?" and (2) "How pleasant or unpleasant does this infant's vocalization sound to you?" The order of the questionnaire items was counterbalanced. Subjects rated these items on 9-point rating scales anchored at the extremes and the midpoint. The scales were described as possessing equal-appearing intervals. After the subjects had completed the rating scales, the nature of the study was explained. In summary, the experimental design included the following independent variables: Cry stimulus (normal versus Down's syndrome), sex of subject, and amount of experience with infants yielding a 2 x 2 x 2 factorial analysis of variance design with repeated measures on the first factor. Separate analyses were conducted on each questionnaire item. Since neither questionnaire item was affected by sex of subject or amount of experience with infants, data were pooled across these variables.
RESULTS AND DISCUSSION The original question addressed by this research was whether adult humans could discriminate the cries of normal and Down's syndrome infants. The answer is clearly that they can. Analysis of responses to the question regarding the infant's need for attention revealed a significant main effect of cry stimulus (F(1,41) = 31.94, p < .001). Normal cries elicited a higher rating that the infant 1Tapes obtained from National Medical Audio-Visual Center, Media Services Section, 1600 Clifton Rd. N.E., Atlanta, Georgia 30333. The cries were elicited by "gentle flicks" to the sole of the infant's foot. No information regarding the sex of infants providing the cries was given on the tapes.
226
FREUDENBERG, DRISCOLL, AND STERN
needed immediate attention (X = 5.90, SD = 1.57) than did Down's syndrome cries (X = 4.60, SD = 1.30). Analysis of ratings of the unpleasantness of the cries also revealed amain e.ffect of cry stimulus (F(1,41) = 26.92, p < .001). Although all cries were rated as unpleasant, the normal infant cries were rated more unpleasant (X = 7,06, SD = 1.04) than were Down's syndrome cries (X = 6.33, SD = 1.25). Responses to the attention and unpleasantness measures were correlated (r(40) = .38, p < .05), indicating that the more unpleasant a cry was rated, the more the infant was perceived as needing attention. In the present study, responses to artificial stimuli were measured. If such responses reflect natural behavior, the findings suggest that adult humans perceive the cries of normal infants as stronger signals for: care-giving behavior than those of Down's syndrome infants. Because amount of experience with infants did not affect reactions to the cries, there may be an unlearned component to this differential response. The ability to discriminate the cries of normal and abnormal infants may have adaptive significance for human evolution in that the energy expended in raising an abnormal infant is biologically wasted. On the other hand, these results may be specific to the fiat, lower pitched cries of Down's syndrome infants and may not reflect a general ability to discriminate between the cries of normal and abnormal infants other than Down's syndrome. It was found that although both sets of cries were perceived as unpleasant, the normal infant cries were rated more unpleasant than the Down's syndrome cries. This finding suggests that the termination of the cry may be negatively reinforcing such that care-giving behaviors that produce cessation of the cry may be increased in frequency. An undifferentiated care-giving response may be shaped by this negative reinforcer. The nonspecific nature of the care-giving response is suggested by previous research (M/iller, Hollien, & Murry, 1974) indicating that adult human females were unable to discriminate among cries elicited by different stimuli even when the cries were produced by their own infants. Although some investigators (Wasz-H6ckert et al., 1968) claim that "hunger" and "pain" cries of infants can be spectrographically differentiated, it is not clear that adult humans discrirninate cry types. It may be that in natural settings, situational stimuli provide more information about the elicitor of the infant's cry. That amount of experience with infants and sex of subjects or their interaction were not related to either questionnaire item may be due to the range of stimuli used. The cry stimuli may have been so distinct from one another as to render the discrimination easy for most subjects regardless of sex and amount of experience with infants. A study employing finer gradations of cry stimuli may provide a more sensitive test of the effects of these variables.
REACTIONS OF ADULTS TO INFANT CRIES
227
REFERENCES Formby, D. Maternal recognition of infant's cry. Developmental Medicine and Child Neurology, 1967, 9, 293-298. Haber, A., Davies, J., & Karelitz, S. Audible characteristics of the cries of normal infants and those with Down's syndrome. Perceptual and Motor Skills, 1966, 23, 745. Karelitz, S., & Fisichelli, V. R. The cry thresholds of normal infants and those with brain damage. Journal o f Pediatrics, 1962, 35, 802. M//ller, E., Hollien, H., & Murry, T. Perceptual responses to infant crying: Identification of cry types. Journal o f Child Lamguage, 1974, 1, 89-95. Wasz-H~ckert, O., Lind, J., Vuorenkoski, V., Partanen, T., & Valanne, E. The infant cry: A spectrographic and auditory analysis. Lavenham: Spastics International Medical Publ. in association with William Heinemann Medical Books Ltd., 1968.